Hoisting and stretching apparatus



VI .llllillll Aug. 18, 1953 v. MALLORY HOISTING AND STRETCHING APPARATUSFiled 001;. 22, 1951 Patented Aug. 18, 1953 UNITED STATES TENT OFFICEHOISTING AND STRETCHING APPARATUS Louis V. Mallory, Rock Island, 111.

Application October 22, 1951, Serial No. 252,566

11 Claims. 1

My invention relates to an improvement upon the hoisting apparatuscovered by Letters Patent of the United States, No. 2,564,541, issuedupon my application on August 14, 1951. Since filing that application, Ihave improved my invention to give the jack a better controlledreleasing feature, by letting the jack with its load down in a positionstep-by-step manner, rather than leaving it to be released by the skillof the operators. Some operators cannot seem to grasp the idea. of justapplying pressure enough to the handle to allow the lower clutch blockto slowly slide down the post, but grab the handle like a pump handleand shove down too hard which results in a chattering jerky descent thatmight be injurious to the bumper brackets of the automobile on whichused.

In order to give the jack this control feature, I have invented aninterlocking assembly of releasing members or straps that are slidablymounted on the clutch blocks of the jack in such a manner that therelease of the clutch elements is effected alternately, when the leveris swung to the full-length of stroke available.

The objects of my invention are to provide simple, convenient means forreleasing hoisting apparatus by successive steps thereby preventingheavy shocks that would occur if the apparatus is entirely released allat once. Other objects will appear from the specification.

I accomplish these objects by the means illustrated in the accompanyingdrawings, in which,

Figure 1 is a front elevation of my apparatus;

Figure 2 is a side elevation partly in section on the line 22 of Figure1, showing both clutch blocks in gripping position against downwardmovement but free to allow upward movement thereof;

. Figure 3 is a sectional detail showing the upper clutch block ingripping position andthe lower block in free position for downwardmovement;

Figure 4 is a top or plan view;

Figure 5 is a sectional detail on the line 55 of Figure 2, but omits theplunger I5 for clearness.

bar I is inserted in a socket 2.I united to or formed integral with abase 2 which may be of any suitable size, shape and material, iron orsteel being preferred.

5 Upon the bar I an upper clutch block 3 and a lower clutch block 4 areslidably mounted. The

upper block 3 has ivotally mounted thereon a forked handle 5 carried bya pivot pin 6. The shorter end of the handle 5 is secured by a pivot 13to the upper end of links I, the lower ends of which are pivotallymounted upon the block 4.

Bores 3.I and 4.I are formed in the blocks 3 and s respectively andextend obliquely upwardly therein with their inner ends adjacent the barI.

Steel balls it and I I are seated in the bores 3.I and M and compressionsprings I2 and I3 are mounted in the bores to bear against the ballstending to drive them toward the inner ends of the bores and intocontact with the bar I. The outer end of the spring I2 bears against thepivot 6 and the outer end of the spring I3 is retained in the bore by aplug I4.

Plungers I5 and I6 are slidably mounted in the blocks 3 and e insuitable bores in the upper part thereof. The inner ends of the plungersare arranged to contact the balls I0 and I I.

A slide II consisting of a flat strip or bar of metal, is mounted uponthe block 3 and secured by an annular spring I8 which is adjustably heldby a thumb screw I9.

The upper end of the slide [1 has an inwardly extending finger or flange20 formed thereon which is arranged to contact the upper end of theplunger I5 when approaching contact with the top of the block 3 and torelease it when moved away from the block 3. The lower end of the slideIT has an upturned lug 22 formed thereon which extends through anopening 24 in the outer fold of the strip 23 in position to. contact theupper end of said fold as the block 3 rises a certain distance.

The body of the slide I? has an opening 2I formed therein through whichthe thumb screw 9 passes and which is larger than the thumb screw so asto permit limited up and down movement of the slide IT relative to theblock 3.

The slide 23 comprises a fiat strip of metal folded upon itself at thelower end and secured to the block a by an annular spring 25 mountedupon the outer fold of the slide 23 and secured by a thumb screw 25 tothe block 4. The thumb screw 26 is threaded into the block 4 and passesthrough an opening 27 in the slide 23 whereby the slide is free to moveup and down within certain limits.

The inner fold of the slide 23 has a finger or flange 28 formed thereonarranged to extend over the plunger i6 and contact the plunger whenapproaching the block 5 whereby the ball II may be forced along the boreM and out of contact with the bar I.

In like manner, the plunger I5 when pushed inwardly by the finger orflange 29, will contact the ball lfi and force it along the bore 3.l andout of contact with the bar I.

The slides ii and 23 are so proportioned that as the handle 25 is raisedupward the full length of its stroke, it will raise the block 3 and theslide I! so that the lug 22 will contact the upper part of slide 25 andraise it whereby the flange 28 will clear the plunger it and allow thespring I3 to force the ball into contact with the bar. i. When in thatposition, the block 4 and ball II will secure the block 4 in stationaryposition upon the bar 5. handle is continued the upper part of the slide23 will hold the lug 22 andslidellagainst further upward motion and theflange-of the slide 3 into contact with the flange 28 and cause theflange 25 to contact the plunger is and-thereby push the ball I 5 out ofcontact with'the bar 1 and allow the block t to descend as far as thelinks I will permit.

The bores in the slides and the thumb screws are so proportioned thatthe handle can be operated through about one-half of its total possibletravel in either direction without causing the lug 22 to contact theupper partof the slide 23 or to cause the flange 28 to contact theplunger! 6 and it is only when the handle is given a full stroke ineither direction that the flanges 26 and 28 Will act upon the plungersl5 and i6. Thus the hoist may be used to raise any object contacted bythe hook 28.! of the block ll by intermediate strokes of the handlethrough the middle portion of its possible travel, and to lower itstep-by-step in full-length strokes of the handle.

When it is desired to lower the load carried by the hook 23.5, thehandle will be given full length strokes and as one of the blocks 3 oris released thereby, the other one will be held in place and in this waythe load can be lowered stepby step to the bottom of its travel and thejerksavoided which would be caused by a longer drop'of the weight.

In order to provide detents to stabilize the slides H and 23 whenholding the plungers, I

form small bores in the upper part of'each r block 3 and i with helicalcompression springs;

by-step descent, while an intermediate manipulation of lever 5 resultsin a step-by-step upward action of the blocks 3 and 4 and hook 233.!

The upper end of the rod i may be provided with a hook 33 whereby thebar may be suspended or anchored by a chain or rope instead of restingupon the base 2.

Various modifications may be made in the form and proportions of variousparts without departing from the spirit of my invention as expressed inthe claims and I do not limit my claims to the precise forms shown inthe drawings.

I claim:

1. In a hoisting jack of the class described, a supporting bar, a pairof clutch blocks lidably When the upward movement of the- Then when thehandle is swung I downwardly full distance, it will carry'the'blockmounted thereon, a manually operable handle pivotally connected to saidblocks and arranged to exert pressure thereon in opposite directionssimultaneously, an oblique bore formed in each block and a ball mountedin each bore springheld in contact with the bar, plungers slidablymounted in the blocks with their inner ends arranged to contact theballs and move them out of contact with the bar when depressed, coactingstripsoperable by the handlein either direction slidably mounted on eachblock and having inturned flanges in position to actuate the plungers,and means whereby intermediate stroke of the handle in the middleportion of its possible travel will advance the blocks in alternationwhile full length strokes of the handle Will cause the blocks to retreatin alternation.

2. In a hoisting jack of the class described, a supporting bar, a pairof clutch blocks slidably mounted thereon, a manually operable handlepivotally connected to said blocks and arranged to exert pressurethereon in opposite directions simultaneously, an oblique bore formedin" each block and a ball mounted in each bore springheld in'contactwith the bar, plungers slidably mounted in the blocks with their innerends arranged to contact the balls andmove them out of contact with thebar when depressed, coacting strips slidably mounted on each blockhaving inturned flanges in position to actuate the plungers, and meanswhereby repeated full strokes of the handle will cause the plungers tocarry the balls out of contact with the bar in alternation and therebyallow retreat of the blocks in alternation.

3. A hoisting jack as described in claim and means whereby shortstrokes'of the handle in the middle of its course of travel will notmove the balls out of contact with the bar simultaneously but will causethe blocks to advance in alternation.

4. In a hoisting jack of the class described, a supporting bar, a pairof clutch blocks slidably mounted thereon, a reciprocating manuallyoperable handle pivotally connected to said blocks and arranged to exertpressure thereon in opposite directions simultaneously when moved ineither direction, a pair of clutch blocks slidably mounted on the barhaving an angular bore formed in each block and a ball mounted in eachbore spring-held in contact with the bar, a plunger slidably mountedineach block with its inner end arranged to contact the ball and roll italong its bore and out of contact with the bar when plungers aredepressed, and coacting means movably mounted on each block arranged tocontact and actuate the plungers in alternation upon the handle beingreciprocated through the full length of its possible stroke.

5. A hoisting jack as described in claim 4, said means being alsoarranged toavoid actuating the plungers when moved only through themiddle portion of its possible travel.

6. Ina hoisting jack of the class described, a supporting bar, a pair ofclutch blocks slidably mounted thereon, a reciprocating manuallyoperable handle pivotally connected to said blocks and arranged to exertpressure thereon in opposite directions simultaneously when moved ineither direction, a pair of clutch blocks slidably mounted on the barhaving an angular bore formed in each black and a ball mounted in eachbore springalong its bore and out of contact with the bar when theplungers are depressed, strip slides mounted upon the clutch blocksrespectively arranged to contact the plungers and move them downwardly,a pair of bores in each of the clutch blocks at right angles to thesupporting bar, with balls movably mounted therein a compression springseated in each of such bores to exert pressure outwardly against theballs, and smaller bores or indentations formed in the slides arrangedto permit the balls to enter therein a short distance whereby the ballsmay detain the slides against accidental movement along the blocks.

'7. In a hoisting jack as described in claim 6, means whereby the ballsmay be forced out of the slides bores in alternation by full movement ofthe handle in reverse directions.

8. A hoisting jack as described in claim 4, said means including smallbores in each of the clutch 1 blocks with balls movably mounted thereinand compression springs seated in the bores arranged to exert pressureoutwardly against the balls, small bores 0r indentations formed in theslides arranged to permit such balls to enter therein a arranged toengage the bore in the strip when 1 the bores in the block and strip arein alignment.

10. In a hoisting jack having a supporting bar, clutch blocks slidablymounted thereon, metal strips slidably secured on said blocks byresilient means, transverse bores formed in said blocks, slightlysmaller bores in said strips, and springheld balls movably mounted inthe transverse bores arranged to engage the bores in the strips when thebores in the blocks and strips are in alignment.

11. In a hoisting jack having a pair of clutch blocks slidably mountedon a support, locking means to lock the clutch blocks against descent,means mounted in said blocks to detain them normally against accidentalmovement, including transverse bores formed therein, and helical springsmounted in the bores arranged to exert pressure against balls mounted insaid bores and cause the balls to engage corresponding bores orindentations in adjacent metal strips slidably mounted on the clutchblocks and arranged to release said locking means by manual movement ofa handle pivotally mounted on the clutch blocks.

LOUIS V. MALLORY.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 383,709 Crecelius May 29, 1888 1,026,347 Foor May 14, 19121,174,363 Starr Mar. 7, 1916 1,874,128 Seeber Aug. 30, 1932 2,196,263Johnston Apr. 9, 1940 2,573,877 Schweitzer Nov. '6, 1951 2,583,544Burdick Jan. 29, 1952 2,597,691 Wikstrom May 2 0, 1952

